Hello Brian
I am interested in the Hartleys, as I may have a connection but not through your branch.
There seem to be at least two probable further children of David and Sarah - Barnet Heartley baptised at the Wesleyan chapel Brighouse (Rastrick is now part of Brighouse), born 21 Jan 1803, parents David and Sally, and Grace, with them in 1841 aged 27.
There are three other Hartleys on the 1851 who are recorded as born Rastrick - James 1807, Simeon 1809, Geo 1813. They are all fancy woollen weavers. I don't know if they are related or not, a quick search hasn't found baptisms for any of them (or Grace).
I expect you know about the Yorkshire Coiners and 'King' David Hartley? If not have a look at this:
www.yorkshirecoiners.comIt might explain why David wasn't a popular name among the Hartleys!
Anne